"Nicht Fr Kugel, Nem Golyonak, Jen Pro Broky just notes constriction and is comparable to Crown over W. In the Austro-Hungarian empire during preliminary proof there was no distinction between smoothbore & rifled tubes as both were fed ball or cylinder, with an allowed clearance of up to 0.5mm. Then all tubes were exposed to some 10 ATM test with a pump apparatus to check for failures. Next rifled tubes were fed a diet of 2 balls or cylinders, what better way to double the weight, while scattergun tubes received a load of 1 1/2 times their shot charge. Most sources give the 1st & 2nd proof for scatterguns was with a solid projectile while the 3rd proof, which could also be an inspection, was with shot. On a tube with choke the diameter was measured forward of the chamber while cylinder tubes had their diameter measured at the muzzle."
http://www.doublegunshop.com/forums/ubbt...true#Post292152Cheers,
Raimey
rse
